Description

Silicon is used as an optical window primarily in the 3 to 5 micron band and as a substrate for production of optical filters. It is frequently used for laser mirrors because of its high thermal conductivity and low density. Silicon is also useful as a transmitter in the *0 micron range. Large blocks wi th polished faces are also employed as targets in neutron physics experiments .Silicon is grown by Czochralski pulling techniques (CZ) and contains some oxygen which causes an absorption band at 9 microns. To avoid this, material can be prepared by a Float-Zone (FZ) process. Optical silicon is generally lightly doped ( 5 to *0 ohm cm) for best transmission above *0 microns. Silicon has a further pass band *0 to **0 microns which is effective only in very high resistivity uncompensated material.